37.20.2 Abstract Display Example

Here is a simple example using functions of the ewoc package to
implement a color components display, an area in a buffer that
represents a vector of three integers (itself representing a 24-bit RGB
value) in various ways.

This example can be extended to be a color selection widget (in
other words, the “controller” part of the “model–view–controller”
design paradigm) by defining commands to modify colorcomp-data
and to finish the selection process, and a keymap to tie it all
together conveniently.